/*!	 layer_composite.h
**	 Composite Layer Class Implementation
**
**	Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**	Copyright (c) 2007, 2008 Chris Moore
**
**	This package is free software; you can redistribute it and/or
**	modify it under the terms of the GNU General Public License as
**	published by the Free Software Foundation; either version 2 of
**	the License, or (at your option) any later version.
**
**	This package is distributed in the hope that it will be useful,
**	but WITHOUT ANY WARRANTY; without even the implied warranty of
**	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
**	General Public License for more details.
**
*/

#ifndef __SYNFIG_LAYER_COMPOSITE_H
#define __SYNFIG_LAYER_COMPOSITE_H

#include <synfig/layer.h>
#include <synfig/color.h>
#include <synfig/cairo_operators.h>

namespace synfig
{

class Layer_NoDeform {};

/*!	\class Layer_Composite
**	 Base class for layers that put stuff on top of lower layers
*/
class Layer_Composite : public Layer
{
private:
    // The amount of composite
    ValueBase param_amount;
    // The blend method for the composition
    ValueBase param_blend_method;

protected:
    // Default constructor. Not used directly.
    explicit Layer_Composite(Real amount = 1.0, Color::BlendMethod blend_method = Color::BLEND_COMPOSITE);

    // Converted blend is used to check if an old version of canvas
    // is used in the composition. Old Straight was used as new Composite
    // TODO:  verify this
    bool converted_blend_;
    // Transparent color is used for old canvas versions.
    // Old Straight plus transparent color seems to be the same new than alpha over.
    bool transparent_color_;

public:
    // Gets the amount of the layer
    float get_amount()const
    {
        return param_amount.get(Real());
    }
    // Sets the amount of the layer and returns this layer
    Layer_Composite& set_amount(float x)
    {
        param_amount.set(x);
        return *this;
    }
    // Gets the blend method of the layer
    Color::BlendMethod get_blend_method()const
    {
        return Color::BlendMethod((param_blend_method.get(int())));
    }
    // Sets the blend method of the layer and returns this layer
    Layer_Composite& set_blend_method(Color::BlendMethod x)
    {
        param_blend_method.set(int(x));
        return *this;
    }
    // Returns true is amount is 1 and blend method is straight
    virtual bool is_solid_color()const
    {
        return param_amount.get(Real()) == 1.0f && param_blend_method.get(int()) == Color::BLEND_STRAIGHT;
    }
    // Returns true if the amount is zero.
    bool is_disabled()const
    {
        return param_amount.get(Real()) == 0.0f;
    }
    // Gets the parameter vocabulary. To be overrided by the derived.
    virtual Vocab get_param_vocab()const;
    // Sets the value for the given parameter.
    virtual bool set_param(const String &param, const ValueBase &value);
    // Gets the value of the given parameter
    virtual ValueBase get_param(const String &param)const;
    // Returns the rectangle that includes the context of the layer and
    // the intersection of the layer in case it is active and not onto
    virtual Rect get_full_bounding_rect(Context context)const;
    // Renders the layer composited on the context and puts it on the target surface.
    virtual bool accelerated_render(Context context, Surface *surface, int quality, const RendDesc &renddesc, ProgressCallback *cb)const;
    virtual bool accelerated_cairorender(Context context, cairo_t *cr, int quality, const RendDesc &renddesc, ProgressCallback *cb)const;

protected:
    virtual rendering::Task::Handle build_composite_task_vfunc(ContextParams context_params)const;
    virtual rendering::Task::Handle build_rendering_task_vfunc(Context context)const;
}; // END of class Layer_Composite

}; // END of namespace synfig

#endif